The present invention generally relates to clutch assemblies having an adjustment mechanism, and more particularly, to a seal for preventing contamination in a portion of the adjustment mechanism.
Clutch assemblies transmit torque from a driving member to a driven member. Clutch assemblies generally include a cover attached to the driving member and a pressure plate that moves relative to the cover to selectively engage friction members attached to the driven member to permit torque transmission. An adjusting ring threadably mounted on the cover provides a fulcrum against which a clutch release mechanism acts to move the pressure plate into and out of engagement with the friction members. In order to compensate for friction member wear, the adjusting ring is rotated in the cover to move the fulcrum position of the clutch release mechanism.
Over time, road dirt and debris, as well as fine particles formed as the pressure plate engages and disengages the friction members, accumulate in various places inside the clutch assembly. One place in particular where the particles accumulate is in a cavity defined in part by the clutch cover and adjusting ring. These particles can contaminate the threaded interface between the clutch cover and adjusting ring, preventing free movement of the adjusting ring relative to the clutch cover. The particles can also become packed between the clutch cover and lugs extending from a surface of the adjusting ring facing the clutch cover, preventing free movement of the adjusting ring. When the particles can prevent clutch adjustment to compensate for friction member wear, they limit a useful life of the clutch assembly or shorten intervals between clutch assembly removal and maintenance.
Past attempts to prevent particles from interfering with free movement of the adjusting ring relative to the clutch cover include positioning rubber seals over the threads at each end of the threaded interface between the clutch cover and adjusting ring. Depending upon the configurations of the seals, particles can still accumulate on exposed portions of the threads not covered by the seals. Over time, the particles can limit adjusting ring movement. Accordingly, there remains a need for preventing particle accumulation at the interface between the clutch cover and adjusting ring.